REGISTRATION RIGHTS AGREEMENT

REGISTRATION RIGHTS AGREEMENT

This Registration Rights Agreement (this “Agreement”) is made and entered into as of March 28, 2007, by and among Calypte Biomedical Corporation, a Delaware corporation (the “Company”), and the investors signatory hereto (each a “Investor” and collectively, the “Investors”).

This Agreement is made pursuant to the Subscription Agreement, dated on or before March 28, 2007, among the Company and the Investors (the “Purchase Agreement”).

The Company and the Investors hereby agree as follows:

1. Definitions. Capitalized terms used and not otherwise defined herein that are defined in the Subscription Agreement shall have the meanings given such terms in the Subscription Agreement. As used in this Agreement, the following terms shall have the respective meanings set forth in this Section 1:

“Effective Date” means the date that the Registration Statement filed pursuant to Section 2(a) is first declared effective by the Commission.

“Effectiveness Date” means (a) with respect to the Registration Statement required to be filed under Section 2(a), the fifth Trading Day following the date on which the Company is notified by the Commission that the First Registration Statement will not be reviewed or is no longer subject to further review and comments and (b) with respect to any additional Registration Statements that may be required pursuant to Section 2(b), (x) if such Registration Statement is required because the Commission shall have notified the Company in writing that certain Registrable Securities were not eligible for inclusion on a previously filed Registration Statement, the date or time on which the Commission shall indicate as being the first date or time that such Registrable Securities may then be included in a Registration Statement, or (y) if such Registration Statement is required for a reason other than as described in (x) above, the date on which the Company first knows, or reasonably should have known, that such additional Registration Statement(s) is required, and (ii) the fifth Trading Day following the date on which the Company is notified by the Commission that such additional Registration Statement will not be reviewed or is no longer subject to further review and comment.

“Effectiveness Period” shall have the meaning set forth in Section 2(a).

“Exchange Act” means the Securities Exchange Act of 1934, as amended.

“Filing Date” means (a) with respect to the initial Registration Statement required to be filed under Section 2(a), the 45^th day following the March 28, 2007 Closing Date and (b) with respect to any additional Registration Statements that may be required pursuant to Section 2(b), the 45^th day following (x) if such Registration Statement is required because the Commission shall have notified the Company in writing that certain Registrable Securities were not eligible for inclusion on a previously filed Registration Statement, the date or time on which the Commission shall indicate as being the first date or time that such Registrable Securities may then be included in a Registration Statement, or (y) if such Registration Statement is required for a reason other than as described in (x) above, the date on which the Company first knows, or reasonably should have known, that such additional Registration Statement(s) is required.

“Investor” or “Investors” means the Investor or Investors, as the case may be, from time to time of Registrable Securities.

“Indemnified Party” shall have the meaning set forth in Section 5(c).

“Indemnifying Party” shall have the meaning set forth in Section 5(c).

“Losses” shall have the meaning set forth in Section 5(a).

“Notes” means, collectively, each of the promissory notes issued or issuable under the Purchase Agreement.

“Proceeding” means an action, claim, suit, investigation or proceeding (including, without limitation, an investigation or partial proceeding, such as a deposition), whether commenced or threatened.

“Prospectus” means the prospectus included in a Registration Statement (including, without limitation, a prospectus that includes any information previously omitted from a prospectus filed as part of an effective registration statement in reliance upon Rule 430A promulgated under the Securities Act), as amended or supplemented by any prospectus supplement, with respect to the terms of the offering of any portion of the Registrable Securities covered by a Registration Statement, and all other amendments and supplements to the Prospectus, including post-effective amendments, and all material incorporated by reference or deemed to be incorporated by reference in such Prospectus.

“Registrable Securities” means the (a) Underlying Shares issuable upon conversion of the Notes (assuming such Notes are held until the maturity date thereof and all interest is accreted to principal thereunder together with any securities issued or issuable upon any stock split, dividend or other distribution, recapitalization or similar event, or any conversion price adjustment with respect thereto), and (b) Warrant Shares issuable upon exercise of the Warrants.

“Registration Statement” means the initial registration statement required to be filed in accordance with Section 2(a) and any additional registration statement, if any, contemplated by Section 2(b), and including, in each case, the Prospectus, amendments and supplements to each such registration statement or Prospectus, including pre- and post-effective amendments, all exhibits thereto, and all material incorporated by reference or deemed to be incorporated by reference in such registration statement.

“Rule 144” means Rule 144 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule.

“Rule 415” means Rule 415 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule.

“Rule 424” means Rule 424 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule.

“Securities Act” means the Securities Act of 1933, as amended.

2. Registration.

(a) On or prior to each Filing Date, the Company shall prepare and file with the Commission a Registration Statement covering the resale of all Registrable Securities not already covered by an existing and effective Registration Statement for an offering to be made on a continuous basis pursuant to Rule 415. The Registration Statement shall be on Form SB-2 or Form S-3 (except if the Company is not then eligible to register for resale the Registrable Securities on Form SB-2 or Form S-3, in which case such registration shall be on another appropriate form for such purpose) and shall contain (except if otherwise required pursuant to written comments received from the Commission upon a review of such Registration Statement) the “Plan of Distribution” attached hereto as Annex A. The Company shall use its best efforts to cause each Registration Statement to be declared effective under the Securities Act within 120 days following the Closing Date and shall use its best efforts to keep each Registration Statement continuously effective under the Securities Act until the second year after the date that the Registration Statement is declared effective by the Commission or such earlier date when all Registrable Securities covered by the Registration Statement have been sold or may be sold without volume restrictions pursuant to Rule 144(k) as determined by the counsel to the Company pursuant to a written opinion letter to such effect, addressed and acceptable to the Company's transfer agent and the affected Investors (the “Effectiveness Period”). The initial Registration Statement shall include a number of Registrable Securities equal to the sum of (a) 100,000,000, the number of Shares issued at the Closing, and (b) 150,000,000, the number of shares issuable upon exercise in full of the Warrants.

(b) If for any reason the Commission does not permit all of the Registrable Securities to be included in the Registration Statement filed pursuant to Section 2(a) or for any other reason all such Registrable Securities are not then included in an effective Registration Statement, then the Company shall prepare and file as soon as possible after the date on which the Commission shall indicate as being the first date or time that such filing may be made, but in any event by the Filing Date therefor, an additional Registration Statement covering the resale of all Registrable Securities not already covered by an existing and effective Registration Statement for an offering to be made on a continuous basis pursuant to Rule 415, on Form SB-2 or Form S-3 (except if the Company is not then eligible to register for resale the Registrable Securities on Form SB-2 or Form S-3, in which case such registration shall be on another appropriate form for such purpose). Each such Registration Statement shall contain (except if otherwise required pursuant to written comments received from the Commission upon a review of such Registration Statement) the “Plan of Distribution” attached hereto as Annex A. The Company shall cause each such Registration Statement to be declared effective under the Securities Act as soon as possible but, in any event, no later than its Effective Date, and shall use its best efforts to keep such Registration Statement continuously effective under the Securities Act during the entire Effectiveness Period.

(c) If a Registration Statement is not filed on or prior to its Filing Date (such failure being referred to as an “Event,” and the date on which such Event occurs being referred to as “Event Date”), then in addition to any other rights the Investors may have under applicable law or at equity: (x) on the Event Date the Company shall pay to each Investor an amount, as partial liquidated damages and not as a penalty, equal to 1.0% of the amount of such Investor’s investment, such payment in cash; and (y) beginning with the one (1) month anniversary following each such Event Date, and on each monthly anniversary thereafter (if the applicable Event shall not have been cured by such date) until the applicable Event is cured, the Company shall pay to each Investor an amount, as partial liquidated damages and not as a penalty, equal to 2.0% of the aggregate amount of such Investor’s investment, such payment being in cash. The parties agree that the Company will not be liable for liquidated damages under this Section in respect of the Warrants. The partial liquidated damages pursuant to the terms hereof shall apply on a daily pro-rata basis for any portion of a month prior to the cure of an Event, including in the case of the first Event Date.

(d) Each Investor agrees to furnish to the Company a completed Questionnaire in the form attached to this Agreement as Annex B (a “Selling Securityholder Questionnaire”). The Company shall not be required to include the Registrable Securities of a Investor in a Registration Statement and shall not be required to pay any liquidated or other damages under Section 2(c) to any Investor who fails to furnish to the Company a fully completed Selling Securityholder Questionnaire at least two Trading Days prior to the Filing Date.

3. Registration Procedures.

In connection with the Company's registration obligations hereunder, the Company shall:

(a) (i) Prepare and file with the Commission such amendments, including post-effective amendments, to each Registration Statement and the Prospectus used in connection therewith as may be necessary to keep such Registration Statement continuously effective as to the applicable Registrable Securities for its Effectiveness Period and prepare and file with the Commission such additional Registration Statements in order to register for resale under the Securities Act all of the Registrable Securities; (ii) cause the related Prospectus to be amended or supplemented by any required Prospectus supplement, and as so supplemented or amended to be filed pursuant to Rule 424; (iii) respond as promptly as reasonably possible to any comments received from the Commission with respect to each Registration Statement or any amendment thereto; and (iv) comply in all material respects with the provisions of the Securities Act and the Exchange Act with respect to the Registration Statements and the disposition of all Registrable Securities covered by each Registration Statement.

(b) Notify the Investors as promptly as reasonably possible (and, in the case of (i)(A) below, not less than three Trading Days prior to such filing) and (if requested by any such Person) confirm such notice in writing no later than one Trading Day following the day (i)(A) when a Prospectus or any Prospectus supplement or post-effective amendment to a Registration Statement is proposed to be filed; and (B) with respect to each Registration Statement or any post-effective amendment, when the same has become effective; (ii) of any request by the Commission or any other Federal or state governmental authority for amendments or supplements to a Registration Statement or Prospectus or for additional information; (iii) of the issuance by the Commission of any stop order suspending the effectiveness of a Registration Statement covering any or all of the Registrable Securities or the initiation of any Proceedings for that purpose; (iv) of the receipt by the Company of any notification with respect to the suspension of the qualification or exemption from qualification of any of the Registrable Securities for sale in any jurisdiction, or the initiation or threatening of any Proceeding for such purpose; and (v) of the occurrence of any event or passage of time that makes the financial statements included in a Registration Statement ineligible for inclusion therein or any statement made in such Registration Statement or Prospectus or any document incorporated or deemed to be incorporated therein by reference untrue in any material respect or that requires any revisions to such Registration Statement, Prospectus or other documents so that, in the case of such Registration Statement or the Prospectus, as the case may be, it will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading.

(c) Use its reasonable best efforts to avoid the issuance of, or, if issued, obtain the withdrawal of (i) any order suspending the effectiveness of a Registration Statement, or (ii) any suspension of the qualification (or exemption from qualification) of any of the Registrable Securities for sale in any jurisdiction, at the earliest practicable moment.

(d) Furnish to each Investor, without charge, at least one conformed copy of each Registration Statement and each amendment thereto and all exhibits to the extent requested by such Person (excluding those previously furnished or incorporated by reference) promptly after the filing of such documents with the Commission.

(e) Upon notification by the Commission that a Registration Statement will not be reviewed or is no longer subject to further review and comments, the Company shall request acceleration of such Registration Statement such that it becomes effective at 5:00 p.m. (New York City time) on the Effective Date.

(f) Deliver to each Investor, by 9:00 a.m. (New York City time) on the day following the Effective Date, without charge, as many copies of each Prospectus or Prospectuses (including each form of prospectus) and each amendment or supplement thereto as such Persons may reasonably request. The Company hereby consents to the use of such Prospectus and each amendment or supplement thereto by each of the selling Investors in connection with the offering and sale of the Registrable Securities covered by such Prospectus and any amendment or supplement thereto.

(g) Prior to any public offering of Registrable Securities, use its best efforts to register or qualify or cooperate with the selling Investors in connection with the registration or qualification (or exemption from such registration or qualification) of such Registrable Securities for offer and sale under the securities or Blue Sky laws of all jurisdictions within the United States, to keep each such registration or qualification (or exemption therefrom) effective during the Effectiveness Period and to do any and all other acts or things necessary or advisable to enable the disposition in such jurisdictions of the Registrable Securities covered by the Registration Statements; provided, that the Company shall not be required to qualify generally to do business in any jurisdiction where it is not then so qualified or subject the Company to any material tax in any such jurisdiction where it is not then so subject.

(h) Cooperate with the Investors to facilitate the timely preparation and delivery of certificates representing Registrable Securities to be delivered to a transferee pursuant to the Registration Statements, which certificates shall be free, to the extent permitted by the Purchase Agreement, of all restrictive legends, and to enable such Registrable Securities to be in such denominations and registered in such names as any such Investors may request.

4. Registration Expenses. All fees and expenses incident to the performance of or compliance with this Agreement by the Company shall be borne by the Company whether or not any Registrable Securities are sold pursuant to a Registration Statement. The fees and expenses referred to in the foregoing sentence shall include, without limitation, (i) all registration and filing fees (including, without limitation, fees and expenses (A) with respect to filings required to be made with any Trading Market on which the Common Stock is then listed for trading, and (B) in compliance with applicable state securities or Blue Sky laws), (ii) printing expenses (including, without limitation, expenses of printing certificates for Registrable Securities and of printing prospectuses if the printing of prospectuses is reasonably requested by the Investors of a majority of the Registrable Securities included in the Registration Statement), (iii) messenger, telephone and delivery expenses, (iv) fees and disbursements of counsel for the Company, (v) Securities Act liability insurance, if the Company so desires such insurance, and (vi) fees and expenses of all other Persons retained by the Company in connection with the consummation of the transactions contemplated by this Agreement. In addition, the Company shall be responsible for all of its internal expenses incurred in connection with the consummation of the transactions contemplated by this Agreement (including, without limitation, all salaries and expenses of its officers and employees performing legal or accounting duties), the expense of any annual audit and the fees and expenses incurred in connection with the listing of the Registrable Securities on any securities exchange as required hereunder.

5. Indemnification.

(a) Indemnification by the Company. The Company shall, notwithstanding any termination of this Agreement, indemnify and hold harmless each Investor, the officers, directors, agents, investment advisors, partners, members, shareholders and employees of each of them, each Person who controls any such Investor (within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act) and the officers, directors, agents and employees of each such controlling Person, to the fullest extent permitted by applicable law, from and against any and all losses, claims, damages, liabilities, costs (including, without limitation, reasonable costs of preparation and reasonable attorneys' fees) and expenses (collectively, “Losses”), as incurred, arising out of or relating to any untrue or alleged untrue statement of a material fact contained in any Registration Statement, any Prospectus or any form of prospectus or in any amendment or supplement thereto or in any preliminary prospectus, or arising out of or relating to any omission or alleged omission of a material fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus or form of prospectus or supplement thereto, in light of the circumstances under which they were made) not misleading, except to the extent, but only to the extent, that (1) such untrue statements or omissions are based solely upon information regarding such Investor furnished in writing to the Company by such Investor expressly for use therein, or to the extent that such information relates to such Investor or such Investor's proposed method of distribution of Registrable Securities and was reviewed and expressly approved in writing by such Investor expressly for use in the Registration Statement, such Prospectus or such form of Prospectus or in any amendment or supplement thereto (it being understood that the Investor has approved Annex A hereto for this purpose) or (2) in the case of an occurrence of an event of the type specified in Section 3(b)(ii)-(v), the use by such Investor of an outdated or defective Prospectus after the Company has notified such Investor in writing that the Prospectus is outdated or defective and prior to the receipt by such Investor of an Advice or an amended or supplemented Prospectus, but only if and to the extent that following the receipt of the Advice or the amended or supplemented Prospectus the misstatement or omission giving rise to such Loss would have been corrected. The Company shall notify the Investors promptly of the institution, threat or assertion of any Proceeding of which the Company is aware in connection with the transactions contemplated by this Agreement.

(b) Indemnification by Investors. Each Investor shall, severally and not jointly, indemnify and hold harmless the Company, its directors, officers, agents and employees, each Person who controls the Company (within the meaning of Section 15 of the Securities Act and Section 20 of the Exchange Act), and the directors, officers, agents or employees of such controlling Persons, to the fullest extent permitted by applicable law, from and against all Losses, as incurred, arising solely out of or based solely upon: (x) such Investor's failure to comply with the prospectus delivery requirements of the Securities Act or (y) any untrue statement of a material fact contained in any Registration Statement, any Prospectus, or any form of prospectus, or in any amendment or supplement thereto, or arising solely out of or based solely upon any omission of a material fact required to be stated therein or necessary to make the statements therein not misleading to the extent, but only to the extent that, (1) such untrue statements or omissions are based solely upon information regarding such Investor furnished in writing to the Company by such Investor expressly for use therein, or to the extent that such information relates to such Investor or such Investor's proposed method of distribution of Registrable Securities and was reviewed and expressly approved in writing by such Investor expressly for use in the Registration Statement (it being understood that the Investor has approved Annex A hereto for this purpose), such Prospectus or such form of Prospectus or in any amendment or supplement thereto or (2) in the case of an occurrence of an event of the type specified in Section 3(b)(ii)-(v), the use by such Investor of an outdated or defective Prospectus after the Company has notified such Investor in writing that the Prospectus is outdated or defective and prior to the receipt by such Investor of an Advice or an amended or supplemented Prospectus, but only if and to the extent that following the receipt of the Advice or the amended or supplemented Prospectus the misstatement or omission giving rise to such Loss would have been corrected. In no event shall the liability of any selling Investor hereunder be greater in amount than the dollar amount of the net proceeds received by such Investor upon the sale of the Registrable Securities giving rise to such indemnification obligation.

(c) Conduct of Indemnification Proceedings. If any Proceeding shall be brought or asserted against any Person entitled to indemnity hereunder (an “Indemnified Party”), such Indemnified Party shall promptly notify the Person from whom indemnity is sought (the “Indemnifying Party”) in writing, and the Indemnifying Party shall assume the defense thereof, including the employment of counsel reasonably satisfactory to the Indemnified Party and the payment of all fees and expenses incurred in connection with defense thereof; provided, that the failure of any Indemnified Party to give such notice shall not relieve the Indemnifying Party of its obligations or liabilities pursuant to this Agreement, except (and only) to the extent that it shall be finally determined by a court of competent jurisdiction (which determination is not subject to appeal or further review) that such failure shall have proximately and materially adversely prejudiced the Indemnifying Party.

An Indemnified Party shall have the right to employ separate counsel in any such Proceeding and to participate in the defense thereof, but the fees and expenses of such counsel shall be at the expense of such Indemnified Party or Parties unless: (1) the Indemnifying Party has agreed in writing to pay such fees and expenses; (2) the Indemnifying Party shall have failed promptly to assume the defense of such Proceeding and to employ counsel reasonably satisfactory to such Indemnified Party in any such Proceeding; or (3) the named parties to any such Proceeding (including any impleaded parties) include both such Indemnified Party and the Indemnifying Party, and such Indemnified Party shall have been advised by counsel that a conflict of interest is likely to exist if the same counsel were to represent such Indemnified Party and the Indemnifying Party (in which case, if such Indemnified Party notifies the Indemnifying Party in writing that it elects to employ separate counsel at the expense of the Indemnifying Party, the Indemnifying Party shall not have the right to assume the defense thereof and such counsel shall be at the expense of the Indemnifying Party). The Indemnifying Party shall not be liable for any settlement of any such Proceeding effected without its written consent, which consent shall not be unreasonably withheld. No Indemnifying Party shall, without the prior written consent of the Indemnified Party, effect any settlement of any pending Proceeding in respect of which any Indemnified Party is a party, unless such settlement includes an unconditional release of such Indemnified Party from all liability on claims that are the subject matter of such Proceeding.

All reasonable fees and expenses of the Indemnified Party (including reasonable fees and expenses to the extent incurred in connection with investigating or preparing to defend such Proceeding in a manner not inconsistent with this Section) shall be paid to the Indemnified Party, as incurred, within ten Trading Days of written notice thereof to the Indemnifying Party (regardless of whether it is ultimately determined that an Indemnified Party is not entitled to indemnification hereunder; provided, that the Indemnifying Party may require such Indemnified Party to undertake to reimburse all such fees and expenses to the extent it is finally judicially determined that such Indemnified Party is not entitled to indemnification hereunder).

(d) Contribution. If a claim for indemnification under Section 5(a) or 5(b) is unavailable to an Indemnified Party (by reason of public policy or otherwise), then each Indemnifying Party, in lieu of indemnifying such Indemnified Party, shall contribute to the amount paid or payable by such Indemnified Party as a result of such Losses, in such proportion as is appropriate to reflect the relative fault of the Indemnifying Party and Indemnified Party in connection with the actions, statements or omissions that resulted in such Losses as well as any other relevant equitable considerations. The relative fault of such Indemnifying Party and Indemnified Party shall be determined by reference to, among other things, whether any action in question, including any untrue or alleged untrue statement of a material fact or omission or alleged omission of a material fact, has been taken or made by, or relates to information supplied by, such Indemnifying Party or Indemnified Party, and the parties' relative intent, knowledge, access to information and opportunity to correct or prevent such action, statement or omission. The amount paid or payable by a party as a result of any Losses shall be deemed to include, subject to the limitations set forth in Section 5(c), any reasonable attorneys' or other reasonable fees or expenses incurred by such party in connection with any Proceeding to the extent such party would have been indemnified for such fees or expenses if the indemnification provided for in this Section was available to such party in accordance with its terms.

The parties hereto agree that it would not be just and equitable if contribution pursuant to this Section 5(d) were determined by pro rata allocation or by any other method of allocation that does not take into account the equitable considerations referred to in the immediately preceding paragraph. Notwithstanding the provisions of this Section 5(d), no Investor shall be required to contribute, in the aggregate, any amount in excess of the amount by which the proceeds actually received by such Investor from the sale of the Registrable Securities subject to the Proceeding exceeds the amount of any damages that such Investor has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission.

The indemnity and contribution agreements contained in this Section are in addition to any liability that the Indemnifying Parties may have to the Indemnified Parties.

6. Miscellaneous.

(a) Remedies. In the event of a breach by the Company or by a Investor, of any of their obligations under this Agreement, each Investor or the Company, as the case may be, in addition to being entitled to exercise all rights granted by law and under this Agreement, including recovery of damages, will be entitled to specific performance of its rights under this Agreement. The Company and each Investor agree that monetary damages would not provide adequate compensation for any losses incurred by reason of a breach by it of any of the provisions of this Agreement and hereby further agrees that, in the event of any action for specific performance in respect of such breach, it shall waive the defense that a remedy at law would be adequate.

(b) Compliance. Each Investor covenants and agrees that it will comply with the prospectus delivery requirements of the Securities Act as applicable to it in connection with sales of Registrable Securities pursuant to the Registration Statement.

(c) Discontinued Disposition. Each Investor agrees by its acquisition of such Registrable Securities that, upon receipt of a notice from the Company of the occurrence of any event of the kind described in Section 3(c), such Investor will forthwith discontinue disposition of such Registrable Securities under the Registration Statement until such Investor's receipt of the copies of the supplemented Prospectus and/or amended Registration Statement or until it is advised in writing (the “Advice”) by the Company that the use of the applicable Prospectus may be resumed, and, in either case, has received copies of any additional or supplemental filings that are incorporated or deemed to be incorporated by reference in such Prospectus or Registration Statement. The Company may provide appropriate stop orders to enforce the provisions of this paragraph. The Company will use its best efforts to ensure that the use of the Prospectus may be resumed as promptly as is practicable. The Company agrees and acknowledges that any periods during which the Investor is required to discontinue the disposition of the Registrable Securities hereunder shall be subject to the provisions of Section 2(c).

(d) Piggy-Back Registrations. If at any time during the Effectiveness Period there is not an effective Registration Statement covering all of the Registrable Securities and the Company shall determine to prepare and file with the Commission a registration statement relating to an offering for its own account or the account of others under the Securities Act of any of its equity securities, other than on Form S-4 or Form S-8 (each as promulgated under the Securities Act) or their then equivalents relating to equity securities to be issued solely in connection with any acquisition of any entity or business or equity securities issuable in connection with stock option or other employee benefit plans, then the Company shall send to each Investor written notice of such determination and, if within fifteen days after receipt of such notice, any such Investor shall so request in writing, the Company shall include in such registration statement all or any part of such Registrable Securities such Investor requests to be registered, subject to customary underwriter cutbacks applicable to all holders of registration rights.

(e) Amendments and Waivers. The provisions of this Agreement, including the provisions of this sentence, may not be amended, modified or supplemented, and waivers or consents to departures from the provisions hereof may not be given, unless the same shall be in writing and signed by the Company and the Investors representing at least a majority of all of the then issued or issuable Notes and Warrants. Notwithstanding the foregoing, a waiver or consent to depart from the provisions hereof with respect to a matter that relates exclusively to the rights of certain Investors and that does not directly or indirectly affect the rights of other Investors may be given by Investors of at least a majority of the Registrable Securities to which such waiver or consent relates, provided, that the provisions of this sentence may not be amended, modified, or supplemented except in accordance with the provisions of the immediately preceding sentence.

(f) Notices. Any and all notices or other communications or deliveries required or permitted to be provided hereunder shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via facsimile at the facsimile telephone number specified in this Section prior to 6:30 p.m. (New York City time) on a Trading Day, (ii) the Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile telephone number specified in this Agreement later than 6:30 p.m. (New York City time) on any date and earlier than 11:59 p.m. (New York City time) on such date, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service, or (iv) upon actual receipt by the party to whom such notice is required to be given. The address for such notices and communications shall be as follows:

If to the Company:	Calypte Biomedical Corporation
	0 Xxxxxxxxxxxx Xxxxx, Xxxxx 000
	Xxxx Xxxxxx, XX 00000
	Facsimile No.: (000) 000-0000
	Attn: Chief Executive Officer

If to an Investor:	To the address set forth under such Investor's name on the signature pages hereto

or such other address as may be designated in writing hereafter, in the same manner, by such Person.

(g) Successors and Assigns. This Agreement shall inure to the benefit of and be binding upon the successors and permitted assigns of each of the parties and shall inure to the benefit of each Investor. The Company may not assign its rights or obligations hereunder without the prior written consent of each Investor. Each Investor may assign its respective rights hereunder in the manner and to the Persons as permitted under the Subscription Agreement so long as such assignment complies with the Subscription Agreement.

(h) Execution and Counterparts. This Agreement may be executed in any number of counterparts, each of which when so executed shall be deemed to be an original and, all of which taken together shall constitute one and the same Agreement. In the event that any signature is delivered by facsimile transmission, such signature shall create a valid binding obligation of the party executing (or on whose behalf such signature is executed) the same with the same force and effect as if such facsimile signature were the original thereof.

(i) Governing Law. All questions concerning the construction, validity, enforcement and interpretation of this Agreement shall be governed by and construed and enforced in accordance with the internal laws of the State of Oregon, without regard to the principles of conflicts of law thereof. Each party agrees that all Proceedings concerning the interpretations, enforcement and defense of the transactions contemplated by this Agreement (whether brought against a party hereto or its respective Affiliates, employees or agents) shall be commenced exclusively in the state and federal courts sitting in the City of Portland (the “Portland Courts”). Each party hereto hereby irrevocably submits to the exclusive jurisdiction of the Portland Courts for the adjudication of any dispute hereunder or in connection herewith or with any transaction contemplated hereby or discussed herein, and hereby irrevocably waives, and agrees not to assert in any Proceeding, any claim that it is not personally subject to the jurisdiction of any Oregon Court, or that such Proceeding has been commenced in an improper or inconvenient forum. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such Proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. Each party hereto hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any Proceeding arising out of or relating to this Agreement or the transactions contemplated hereby. If either party shall commence a Proceeding to enforce any provisions of this Agreement, then the prevailing party in such Proceeding shall be reimbursed by the other party for its attorney’s fees and other costs and expenses incurred with the investigation, preparation and prosecution of such Proceeding.

(j) Cumulative Remedies. The remedies provided herein are cumulative and not exclusive of any remedies provided by law.

(k) Severability. If any term, provision, covenant or restriction of this Agreement is held by a court of competent jurisdiction to be invalid, illegal, void or unenforceable, the remainder of the terms, provisions, covenants and restrictions set forth herein shall remain in full force and effect and shall in no way be affected, impaired or invalidated, and the parties hereto shall use their reasonable efforts to find and employ an alternative means to achieve the same or substantially the same result as that contemplated by such term, provision, covenant or restriction. It is hereby stipulated and declared to be the intention of the parties that they would have executed the remaining terms, provisions, covenants and restrictions without including any of such that may be hereafter declared invalid, illegal, void or unenforceable.

(l) Headings. The headings in this Agreement are for convenience of reference only and shall not limit or otherwise affect the meaning hereof.

(m) Independent Nature of Investors' Obligations and Rights. The obligations of each Investor under this Agreement are several and not joint with the obligations of each other Investor, and no Investor shall be responsible in any way for the performance of the obligations of any other Investor under this Agreement. Nothing contained herein or in any Transaction Document, and no action taken by any Investor pursuant thereto, shall be deemed to constitute the Investors as a partnership, an association, a joint venture or any other kind of entity, or create a presumption that the Investors are in any way acting in concert or as a group with respect to such obligations or the transactions contemplated by this Agreement or any other Transaction Document. Each Investor acknowledges that no other Investor has acted as agent for such Investor in connection with making its investment hereunder and that no Investor will be acting as agent of such Investor in connection with monitoring its investment in the Securities or enforcing its rights under the Transaction Documents. Each Investor shall be entitled to independently protect and enforce its rights, including without limitation the rights arising out of this Agreement, and it shall not be necessary for any other Investor to be joined as an additional party in any Proceeding for such purpose. The Company acknowledges that each of the Investors has been provided with the same Registration Rights Agreement for the purpose of closing a transaction with multiple Investors and not because it was required or requested to do so by any Investor.

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SIGNATURE PAGES TO FOLLOW]

IN WITNESS WHEREOF, the parties have executed this Registration Rights Agreement as of the date first written above.


	CALYPTE BIOMEDICAL CORPORATION

	By:
		Name: Xxxxxxx Xxxxxxxxxx
		Title: Executive Vice President

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		SIGNATURE PAGES OF INVESTORS TO FOLLOW]

IN WITNESS WHEREOF, the parties have executed this Registration Rights Agreement as of the date first written above.

NAME OF INVESTING ENTITY

AUTHORIZED SIGNATORY

By:

Name:

Title:

ADDRESS FOR NOTICE

c/o:

Street:

City/State/Zip:

Attention:

Tel:

Fax:

Email:

Annex A

Plan of Distribution

The Selling Stockholders and any of their pledgees, donees, transferees, assignees and successors-in-interest may, from time to time, sell any or all of their shares of Common Stock on any stock exchange, market or trading facility on which the shares are traded or in private transactions. These sales may be at fixed or negotiated prices. The Selling Stockholders may use any one or more of the following methods when selling shares:

·	ordinary brokerage transactions and transactions in which the broker-dealer solicits Investors;

·	block trades in which the broker-dealer will attempt to sell the shares as agent but may position and resell a portion of the block as principal to facilitate the transaction;

·	purchases by a broker-dealer as principal and resale by the broker-dealer for its account;

·	an exchange distribution in accordance with the rules of the applicable exchange;

·	privately negotiated transactions;

·	to cover short sales made after the date that this Registration Statement is declared effective by the Commission;

·	broker-dealers may agree with the Selling Stockholders to sell a specified number of such shares at a stipulated price per share;

·	a combination of any such methods of sale; and

·	any other method permitted pursuant to applicable law.

The Selling Stockholders may also sell shares under Rule 144 under the Securities Act, if available, rather than under this prospectus.

Broker-dealers engaged by the Selling Stockholders may arrange for other brokers-dealers to participate in sales. Broker-dealers may receive commissions or discounts from the Selling Stockholders (or, if any broker-dealer acts as agent for the purchaser of shares, from the purchaser) in amounts to be negotiated. The Selling Stockholders do not expect these commissions and discounts to exceed what is customary in the types of transactions involved.

The Selling Stockholders may from time to time pledge or grant a security interest in some or all of the Shares owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell shares of Common Stock from time to time under this prospectus, or under an amendment to this prospectus under Rule 424(b)(3) or other applicable provision of the Securities Act of 1933 amending the list of selling stockholders to include the pledgee, transferee or other successors in interest as selling stockholders under this prospectus.

Upon the Company being notified in writing by a Selling Stockholder that any material arrangement has been entered into with a broker-dealer for the sale of Common Stock through a block trade, special offering, exchange distribution or secondary distribution or a purchase by a broker or dealer, a supplement to this prospectus will be filed, if required, pursuant to Rule 424(b) under the Securities Act, disclosing (i) the name of each such Selling Stockholder and of the participating broker-dealer(s), (ii) the number of shares involved, (iii) the price at which such the shares of Common Stock were sold, (iv)the commissions paid or discounts or concessions allowed to such broker-dealer(s), where applicable, (v) that such broker-dealer(s) did not conduct any investigation to verify the information set out or incorporated by reference in this prospectus, and (vi) other facts material to the transaction. In addition, upon the Company being notified in writing by a Selling Stockholder that a donee or pledge intends to sell more than 500 shares of Common Stock, a supplement to this prospectus will be filed if then required in accordance with applicable securities law.

The Selling Stockholders also may transfer the shares of Common Stock in other circumstances, in which case the transferees, pledgees or other successors in interest will be the selling beneficial owners for purposes of this prospectus.

The Selling Stockholders and any broker-dealers or agents that are involved in selling the shares may be deemed to be “underwriters” within the meaning of the Securities Act in connection with such sales. In such event, any commissions received by such broker-dealers or agents and any profit on the resale of the shares purchased by them may be deemed to be underwriting commissions or discounts under the Securities Act. Discounts, concessions, commissions and similar selling expenses, if any, that can be attributed to the sale of Securities will be paid by the Selling Stockholder and/or the purchasers. Each Selling Stockholder has represented and warranted to the Company that it acquired the securities subject to this registration statement in the ordinary course of such Selling Stockholder’s business and, at the time of its purchase of such securities such Selling Stockholder had no agreements or understandings, directly or indirectly, with any person to distribute any such securities.

Each Selling Stockholder has acknowledged that Shares registered on this Registration Statement may not be used to cover short sales of Common Stock made prior to the date on which this Registration Statement shall have been declared effective by the Commission. If a Selling Stockholder uses this prospectus for any sale of the Common Stock, it will be subject to the prospectus delivery requirements of the Securities Act. The Selling Stockholders will be responsible to comply with the applicable provisions of the Securities Act and Exchange Act, and the rules and regulations thereunder promulgated, including, without limitation, Regulation M, as applicable to such Selling Stockholders in connection with resales of their respective shares under this Registration Statement.

The Company is required to pay all fees and expenses incident to the registration of the shares, but the Company will not receive any proceeds from the sale of the Common Stock. The Company has agreed to indemnify the Selling Stockholders against certain losses, claims, damages and liabilities, including liabilities under the Securities Act.

Annex B

CALYPTE BIOMEDICAL CORPORATION

Selling Securityholder Notice and Questionnaire

The undersigned beneficial owner of common stock (the “Common Stock”), of Calypte Biomedical Corporation (the “Company”) understands that the Company has filed or intends to file with the Securities and Exchange Commission (the “Commission”) a Registration Statement for the registration and resale of the Registrable Securities, in accordance with the terms of the Registration Rights Agreement, dated as of February [ ], 2007(the “Registration Rights Agreement”), among the Company and the Investors named therein. A copy of the Registration Rights Agreement is available from the Company upon request at the address set forth below. All capitalized terms used and not otherwise defined herein shall have the meanings ascribed thereto in the Registration Rights Agreement.

The undersigned hereby provides the following information to the Company and represents and warrants that such information is accurate:

QUESTIONNAIRE

1.	Name.

	(a)	Full Legal Name of Selling Securityholder


	(b)	Full Legal Name of Registered Holder (if not the same as (a) above) through which Registrable Securities Listed in Item 3 below are held:


	(c)	Full Legal Name of Natural Control Person (which means a natural person who directly or indirectly alone or with others has power to vote or dispose of the securities covered by the questionnaire):







2. Address for Notices to Selling Securityholder:

Telephone:
Fax:
Contact Person:

3. Beneficial Ownership of Registrable Securities:

	Type and Principal Amount of Registrable Securities beneficially owned:

4. Broker-Dealer Status:

(a)

Are you a broker-dealer?

Yes o No o

Note:

If yes, the Commission’s staff has indicated that you should be identified as an underwriter in the Registration Statement.

(b)

Are you an affiliate of a broker-dealer?

Yes o No o

(c)

If you are an affiliate of a broker-dealer, do you certify that you bought the Registrable Securities in the ordinary course of business, and at the time of the purchase of the Registrable Securities to be resold, you had no agreements or understandings, directly or indirectly, with any person to distribute the Registrable Securities?

Yes o No o

Note:

If no, the Commission’s staff has indicated that you should be identified as an underwriter in the Registration Statement.

5. Beneficial Ownership of Other Securities of the Company Owned by the Selling Securityholder.

Except as set forth below in this Item 5, the undersigned is not the beneficial or registered owner of any securities of the Company other than the Registrable Securities listed above in Item 3.

Type and Amount of Other Securities beneficially owned by the Selling Securityholder:

6. Relationships with the Company:

Except as set forth below, neither the undersigned nor any of its affiliates, officers, directors or principal equity holders (owners of 5% of more of the equity securities of the undersigned) has held any position or office or has had any other material relationship with the Company (or its predecessors or affiliates) during the past three years.

State any exceptions here:

The undersigned agrees to promptly notify the Company of any inaccuracies or changes in the information provided herein that may occur subsequent to the date hereof and prior to the Effective Date for the Registration Statement.

By signing below, the undersigned consents to the disclosure of the information contained herein in its answers to Items 1 through 6 and the inclusion of such information in the Registration Statement and the related prospectus. The undersigned understands that such information will be relied upon by the Company in connection with the preparation or amendment of the Registration Statement and the related prospectus.

IN WITNESS WHEREOF the undersigned, by authority duly given, has caused this Notice and Questionnaire to be executed and delivered either in person or by its duly authorized agent.

Dated:	Beneficial Owner:

	By:
		Name:
		Title:

PLEASE FAX A COPY OF THE COMPLETED AND EXECUTED NOTICE AND QUESTIONNAIRE, AND RETURN THE ORIGINAL BY OVERNIGHT MAIL,

TO: CALYPTE BIOMEDICAL CORPORATION

000-000-0000

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REGISTRATION RIGHTS AGREEMENT

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